acquisition of objective data during transapical neochordae implantation

Conditions: Mitral Valve Insufficiency; Mitral Regurgitation

Summary: mitral valve repair (mvr) is the gold standard treatment for primary mitral regurgitation. implantation of artificial gore-tex chordae (or neochordae implantation) is often used for mvr. the neochord ds1000 (neochord inc., minneapolis, usa) is a device designed to deploy neochordae through transapical access in a beating heart and without cardiopulmonary bypass. neochord system is ce marked and therefore authorized for use in europe. procedure is conducted under 3d transesophageal echocardiography (tee) guidance. the device is introduced through the apex of the left ventricular (lv) and the prolapsed leaflet is grabbed and harpooned. the neochordae are thus stretched between the valve and the lv apex. neochordae length can be precisely adapted to restore a normal coaptation, to treat the regurgitation. recently, the principal investigator's teams (heart surgery department at hospices civils de lyon and laboratoire de génie electrique et ferromagnétique lab at institut national des sciences appliquées (insa) de lyon, france) created a platform allowing the measurement of the tension applied on neochordae during a neochord procedure. a dedicated protocol was designed and approved by the ethical committee of the french society of cardiology. the measurement was performed in 7 patients. this preliminary study shows that the technic is safe. it also suggests that chordal tension might be correlated to the quality of mvr: the sub-valvular apparatus appears to be in a low stress state when the structure and the function of the valve are restored. these first findings raise new questions: 1. the mechanism involved in the changes in tensions during chordal length adjustment cannot be understood with current standard medical imaging tools. numerical simulation technologies could bring physical data in order to approach physical phenomenon underlying these findings. 2. novel chordal tension measurement tools could lead to a change in current paradigm enabling a mvr based on objective data measurement, instead of sole morphological analysis. prognostic value of chordal tension must be studied through a larger clinical study and a systematic protocol. a large consortium involving physicians and scientists has been created to address those questions, and a large national funding has been raised to fulfil our objectives over a 4 years period (simr project). the present clinical study is the core of this large project.


Eligibility criteria:
inclusion criteria: * adults (≥ 18 years old) * patient candidate for neochord procedure after validation by the local heart-team * severe symptomatic mr due to a posterior prolapses, involving mainly the p2 segment (with a variable extension on p1 or p3, but never involving the commissures or the anterior leaflet). also, a lai (leaflet to annulus index) \>1,25 will be required. * and considered as high-risk for conventional surgery (mainly because of frailty) after selection by our heart team. * patient who has provided his written informed consent to participate in the study * patient affiliated to a social health insurance. exclusion criteria: * patient with contraindication for neochord technic including: * patient with secondary mr * lv dilatation with initial tethering * central component to regurgitant jet * calcified leaflets segments. * patient with contraindication for cardiovascular magnetic resonance (cmr) imaging: * patients without sinus rhythm * regular mri contraindications (e.g. a pacemaker, defibrillator or metallic (ferromagnetic) body, a known allergy to gadolinium) * contraindication for gadolinium infusion : glomerular filtration rate (gfr) \<30 ml / min * patient unable to understand the purpose of the study * patient participating in another trial that would interfere with this study * female patient who is pregnant or lactating * patients under judicial protection

Keywords: primary mitral regurgitation mitral valve repair heart surgery neochord ds1000 intraoperative chordal tension tension measurement cardiac magnetic resonance imaging postoperative echocardiographic evaluation